The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 18, 1991
Filed:
Mar. 02, 1990
Kiyotaka Iiyama, Sakuramura, JP;
Kunio Hayakawa, Gotenba, JP;
Masahiro Nakata, Osaka, JP;
Kaoru Kodera, Osaka, JP;
Osamu Miyazaki, Osaka, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A leuco dye having the formula ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each represent a lower alkyl group; R.sup.5 represents an .alpha.-naphthyl group, .beta.-naphthyl group or ##STR2## wherein R.sup.6 represents --NHCOR.sup.9, a halogen or an amino group which is unsubstituted or substituted by one or two C.sub.1 -C.sub.4 alkyl groups which are the same or different; and R.sup.7, R.sup.8 and R.sup.9 each represent hydrogen or a lower alkyl group, provided that when both R.sup.7 and R.sup.8 are hydrogen, R.sup.6 represents --NHCOR.sup.9 or bromine. These dyes absorb in the near-infrared region and yield colored images with a color developer therefor with excellent preservability.